<p>From the official Oracle Javadoc:</p>
<blockquote>
<p>NOTE: The functionality of this Enumeration interface is duplicated by the Iterator interface. In addition, Iterator adds an optional remove operation, and has shorter method names. New implementations should consider using Iterator in preference to Enumeration.</p>
</blockquote>
<p>The following code:</p>
<pre>
public class MyClass implements Enumeration {  // Noncompliant
  /* ... */
}
</pre>
<p>should be refactored into:</p>
<pre>
public class MyClass implements Iterator {     // Compliant
  /* ... */
}
</pre>

